This application relates to mechanisms for holding material in an optical setup fo analysis.
The precise measure and characterization of the optical properties of materials is an important part of research and development in numerous technologies. For example, many important optical materials exhibit birefringence. Birefringence means that different linear polarizations of light travel at different speeds through the material. These different polarizations are most often considered as two components of the polarized light, one component being orthogonal to the other. Birefringence is an intrinsic property of many optical materials, and may also be induced by external forces applied to the material.
The need for precise measurement of the birefringence properties of an optical element has become increasingly important in a number of technical applications. For instance, it is important to specify linear birefringence in optical elements that are used in high-precision instruments employed in semiconductor and other industries. Many applications require that the birefringence of the optical element be measured across the entire surface of the element.
Optical elements are constructed of various types of glasses and polymeric films and other material. For convenience, an optical element will hereafter be referred to as a xe2x80x9csample.xe2x80x9d The mechanisms for investigating the optical properties of the sample include a light beam that is transmitted through the sample for analysis. The arrangement of the components for generating, directing, conditioning (polarizing, etc.), and detecting the light beam will be referred to as an optical setup.
Birefringence measurement of a sample requires that the sample be secured in a holder in a manner such that no stress is induced in the sample (hence, no birefringence due to external forces is induced). The sample is moved relative to the light beam to enable birefringence measurement of the sample across the surface of the sample at a predetermined number of locations.
Samples come in many different sizes and shapes, depending on the particular application. A common shape for such a sample is cylindrical, in any of a wide range of diameters.
The present invention is directed to a holder for optical elements, or samples, in an optical setup.
A holder made in accordance with the present invention is readily adjustable to accommodate samples of various sizes, such as cylindrical shaped samples of various diameters.
The adjustable holder is designed to provide stable support for the sample, irrespective of the size of the sample.
The holder supports the sample in a way that maximizes the area of the sample through which a light beam may pass.
The holder supports the sample in a manner that does not stress the sample to induce birefringence into the sample. The holder allows movement of the holder and supported sample relative to the light beam.
Other advantages and features of the present invention will become clear upon study of the following portion of this specification and the drawings.